Base slab construction below grade

Is it OK to build the base slab below grade? I would then rebuild my patio pavers around the unit, with the grade ultimately being about 1/2 way up the first center block level. My concern is about burying the mortar and grouting below grade; would it deteriorate the strength of the mortar (if the ground stays moist)? Thanks.

Question - Are you building your base 5 cinder block layers in height? Could the below-grade construction be averted if you built your oven base 4 cinder block layers in height?

Not really a height issue; the wife wanted the slab below grade so we could put our patio pavers on top of the slab and butt the pavers right up to the base walls. I’m still working on her to accept a grade level slab; maybe tinting the base to a similar color.


Instead of a base slab - you could always build a cinder block footer.

Just picture a cinder block base - 5 rows above ground… 2 rows below ground / grade.

The 2 rows of cinder block that are below grade - the each core is full of concrete mix and rebar. Every core has rebar…

Once the oven base (and oven) are complete, you can simply bring the pavers to the base.


LINK - Here is a below grade install / no base slab

LINK - Here is a pic of what it will look like when complete

Good option. Though not sure i can dig down that deep. I may stay with the slab. It would be a strong and level base. Either way, this oven is going up soon.

Thank you,